/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Quake III Arena source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
 */
// world.c -- world query functions

#include "server.h"

/*
================
SV_ClipHandleForEntity

Returns a headnode that can be used for testing or clipping to a
given entity.  If the entity is a bsp model, the headnode will
be returned, otherwise a custom box tree will be constructed.
================
 */
clipHandle_t SV_ClipHandleForEntity(const sharedEntity_t *ent) {
    if (ent->r.bmodel) {
        // explicit hulls in the BSP model
        return CM_InlineModel(ent->s.modelindex);
    }
    if (ent->r.svFlags & SVF_CAPSULE) {
        // create a temp capsule from bounding box sizes
        return CM_TempBoxModel(ent->r.mins, ent->r.maxs, qtrue);
    }

    // create a temp tree from bounding box sizes
    return CM_TempBoxModel(ent->r.mins, ent->r.maxs, qfalse);
}

/*
===============================================================================

ENTITY CHECKING

To avoid linearly searching through lists of entities during environment testing,
the world is carved up with an evenly spaced, axially aligned bsp tree.  Entities
are kept in chains either at the final leafs, or at the first node that splits
them, which prevents having to deal with multiple fragments of a single entity.

===============================================================================
 */

typedef struct worldSector_s {
    int axis; // -1 = leaf node
    float dist;
    struct worldSector_s * children[2];
    svEntity_t *entities;
} worldSector_t;

#define	AREA_DEPTH	4
#define	AREA_NODES	64

worldSector_t sv_worldSectors[AREA_NODES];
int sv_numworldSectors;

/*
===============
SV_SectorList_f
===============
 */
void SV_SectorList_f(void) {
    int i, c;
    worldSector_t *sec;
    svEntity_t *ent;

    for (i = 0; i < AREA_NODES; i++) {
        sec = &sv_worldSectors[i];

        c = 0;
        for (ent = sec->entities; ent; ent = ent->nextEntityInWorldSector) {
            c++;
        }
        Com_Printf("sector %i: %i entities\n", i, c);
    }
}

/*
===============
SV_CreateworldSector

Builds a uniformly subdivided tree for the given world size
===============
 */
static worldSector_t *SV_CreateworldSector(int depth, vec3_t mins, vec3_t maxs) {
    worldSector_t *anode;
    vec3_t size;
    vec3_t mins1, maxs1, mins2, maxs2;

    anode = &sv_worldSectors[sv_numworldSectors];
    sv_numworldSectors++;

    if (depth == AREA_DEPTH) {
        anode->axis = -1;
        anode->children[0] = anode->children[1] = NULL;
        return anode;
    }

    VectorSubtract(maxs, mins, size);
    if (size[0] > size[1]) {
        anode->axis = 0;
    } else {
        anode->axis = 1;
    }

    anode->dist = 0.5 * (maxs[anode->axis] + mins[anode->axis]);
    VectorCopy(mins, mins1);
    VectorCopy(mins, mins2);
    VectorCopy(maxs, maxs1);
    VectorCopy(maxs, maxs2);

    maxs1[anode->axis] = mins2[anode->axis] = anode->dist;

    anode->children[0] = SV_CreateworldSector(depth + 1, mins2, maxs2);
    anode->children[1] = SV_CreateworldSector(depth + 1, mins1, maxs1);

    return anode;
}

/*
===============
SV_ClearWorld

===============
 */
void SV_ClearWorld(void) {
    clipHandle_t h;
    vec3_t mins, maxs;

    Com_Memset(sv_worldSectors, 0, sizeof (sv_worldSectors));
    sv_numworldSectors = 0;

    // get world map bounds
    h = CM_InlineModel(0);
    CM_ModelBounds(h, mins, maxs);
    SV_CreateworldSector(0, mins, maxs);
}

/*
===============
SV_UnlinkEntity

===============
 */
void SV_UnlinkEntity(sharedEntity_t *gEnt) {
    svEntity_t *ent;
    svEntity_t *scan;
    worldSector_t *ws;

    ent = SV_SvEntityForGentity(gEnt);

    gEnt->r.linked = qfalse;

    ws = ent->worldSector;
    if (!ws) {
        return; // not linked in anywhere
    }
    ent->worldSector = NULL;

    if (ws->entities == ent) {
        ws->entities = ent->nextEntityInWorldSector;
        return;
    }

    for (scan = ws->entities; scan; scan = scan->nextEntityInWorldSector) {
        if (scan->nextEntityInWorldSector == ent) {
            scan->nextEntityInWorldSector = ent->nextEntityInWorldSector;
            return;
        }
    }

    Com_Printf("WARNING: SV_UnlinkEntity: not found in worldSector\n");
}


/*
===============
SV_LinkEntity

===============
 */
#define MAX_TOTAL_ENT_LEAFS		128

void SV_LinkEntity(sharedEntity_t *gEnt) {
    worldSector_t *node;
    int leafs[MAX_TOTAL_ENT_LEAFS];
    int cluster;
    int num_leafs;
    int i, j, k;
    int area;
    int lastLeaf;
    float *origin, *angles;
    svEntity_t *ent;

    ent = SV_SvEntityForGentity(gEnt);

    if (ent->worldSector) {
        SV_UnlinkEntity(gEnt); // unlink from old position
    }

    // encode the size into the entityState_t for client prediction
    if (gEnt->r.bmodel) {
        gEnt->s.solid = SOLID_BMODEL; // a solid_box will never create this value
    } else if (gEnt->r.contents & (CONTENTS_SOLID | CONTENTS_BODY)) {
        // assume that x/y are equal and symetric
        i = gEnt->r.maxs[0];
        if (i < 1)
            i = 1;
        if (i > 255)
            i = 255;

        // z is not symetric
        j = (-gEnt->r.mins[2]);
        if (j < 1)
            j = 1;
        if (j > 255)
            j = 255;

        // and z maxs can be negative...
        k = (gEnt->r.maxs[2] + 32);
        if (k < 1)
            k = 1;
        if (k > 255)
            k = 255;

        gEnt->s.solid = (k << 16) | (j << 8) | i;
    } else {
        gEnt->s.solid = 0;
    }

    // get the position
    origin = gEnt->r.currentOrigin;
    angles = gEnt->r.currentAngles;

    // set the abs box
    if (gEnt->r.bmodel && (angles[0] || angles[1] || angles[2])) {
        // expand for rotation
        float max;
        int i;

        max = RadiusFromBounds(gEnt->r.mins, gEnt->r.maxs);
        for (i = 0; i < 3; i++) {
            gEnt->r.absmin[i] = origin[i] - max;
            gEnt->r.absmax[i] = origin[i] + max;
        }
    } else {
        // normal
        VectorAdd(origin, gEnt->r.mins, gEnt->r.absmin);
        VectorAdd(origin, gEnt->r.maxs, gEnt->r.absmax);
    }

    // because movement is clipped an epsilon away from an actual edge,
    // we must fully check even when bounding boxes don't quite touch
    gEnt->r.absmin[0] -= 1;
    gEnt->r.absmin[1] -= 1;
    gEnt->r.absmin[2] -= 1;
    gEnt->r.absmax[0] += 1;
    gEnt->r.absmax[1] += 1;
    gEnt->r.absmax[2] += 1;

    // link to PVS leafs
    ent->numClusters = 0;
    ent->lastCluster = 0;
    ent->areanum = -1;
    ent->areanum2 = -1;

    //get all leafs, including solids
    num_leafs = CM_BoxLeafnums(gEnt->r.absmin, gEnt->r.absmax,
            leafs, MAX_TOTAL_ENT_LEAFS, &lastLeaf);

    // if none of the leafs were inside the map, the
    // entity is outside the world and can be considered unlinked
    if (!num_leafs) {
        return;
    }

    // set areas, even from clusters that don't fit in the entity array
    for (i = 0; i < num_leafs; i++) {
        area = CM_LeafArea(leafs[i]);
        if (area != -1) {
            // doors may legally straggle two areas,
            // but nothing should evern need more than that
            if (ent->areanum != -1 && ent->areanum != area) {
                if (ent->areanum2 != -1 && ent->areanum2 != area && sv.state == SS_LOADING) {
                    Com_DPrintf("Object %i touching 3 areas at %f %f %f\n",
                            gEnt->s.number,
                            gEnt->r.absmin[0], gEnt->r.absmin[1], gEnt->r.absmin[2]);
                }
                ent->areanum2 = area;
            } else {
                ent->areanum = area;
            }
        }
    }

    // store as many explicit clusters as we can
    ent->numClusters = 0;
    for (i = 0; i < num_leafs; i++) {
        cluster = CM_LeafCluster(leafs[i]);
        if (cluster != -1) {
            ent->clusternums[ent->numClusters++] = cluster;
            if (ent->numClusters == MAX_ENT_CLUSTERS) {
                break;
            }
        }
    }

    // store off a last cluster if we need to
    if (i != num_leafs) {
        ent->lastCluster = CM_LeafCluster(lastLeaf);
    }

    gEnt->r.linkcount++;

    // find the first world sector node that the ent's box crosses
    node = sv_worldSectors;
    while (1) {
        if (node->axis == -1)
            break;
        if (gEnt->r.absmin[node->axis] > node->dist)
            node = node->children[0];
        else if (gEnt->r.absmax[node->axis] < node->dist)
            node = node->children[1];
        else
            break; // crosses the node
    }

    // link it in
    ent->worldSector = node;
    ent->nextEntityInWorldSector = node->entities;
    node->entities = ent;

    gEnt->r.linked = qtrue;
}

/*
============================================================================

AREA QUERY

Fills in a list of all entities who's absmin / absmax intersects the given
bounds.  This does NOT mean that they actually touch in the case of bmodels.
============================================================================
 */

typedef struct {
    const float *mins;
    const float *maxs;
    int *list;
    int count, maxcount;
} areaParms_t;

/*
====================
SV_AreaEntities_r

====================
 */
static void SV_AreaEntities_r(worldSector_t *node, areaParms_t *ap) {
    svEntity_t *check, *next;
    sharedEntity_t *gcheck;
    int count;

    count = 0;

    for (check = node->entities; check; check = next) {
        next = check->nextEntityInWorldSector;

        gcheck = SV_GEntityForSvEntity(check);

        if (gcheck->r.absmin[0] > ap->maxs[0]
                || gcheck->r.absmin[1] > ap->maxs[1]
                || gcheck->r.absmin[2] > ap->maxs[2]
                || gcheck->r.absmax[0] < ap->mins[0]
                || gcheck->r.absmax[1] < ap->mins[1]
                || gcheck->r.absmax[2] < ap->mins[2]) {
            continue;
        }

        if (ap->count == ap->maxcount) {
            Com_Printf("SV_AreaEntities: MAXCOUNT\n");
            return;
        }

        ap->list[ap->count] = check - sv.svEntities;
        ap->count++;
    }

    if (node->axis == -1) {
        return; // terminal node
    }

    // recurse down both sides
    if (ap->maxs[node->axis] > node->dist) {
        SV_AreaEntities_r(node->children[0], ap);
    }
    if (ap->mins[node->axis] < node->dist) {
        SV_AreaEntities_r(node->children[1], ap);
    }
}

/*
================
SV_AreaEntities
================
 */
int SV_AreaEntities(const vec3_t mins, const vec3_t maxs, int *entityList, int maxcount) {
    areaParms_t ap;

    ap.mins = mins;
    ap.maxs = maxs;
    ap.list = entityList;
    ap.count = 0;
    ap.maxcount = maxcount;

    SV_AreaEntities_r(sv_worldSectors, &ap);

    return ap.count;
}



//===========================================================================

typedef struct {
    vec3_t boxmins, boxmaxs; // enclose the test object along entire move
    const float *mins;
    const float *maxs; // size of the moving object
    const float *start;
    vec3_t end;
    trace_t trace;
    int passEntityNum;
    int contentmask;
    int capsule;
} moveclip_t;

/*
====================
SV_ClipToEntity

====================
 */
void SV_ClipToEntity(trace_t *trace, const vec3_t start, const vec3_t mins, const vec3_t maxs, const vec3_t end, int entityNum, int contentmask, int capsule) {
    sharedEntity_t *touch;
    clipHandle_t clipHandle;
    float *origin, *angles;

    touch = SV_GentityNum(entityNum);

    Com_Memset(trace, 0, sizeof (trace_t));

    // if it doesn't have any brushes of a type we
    // are looking for, ignore it
    if (!(contentmask & touch->r.contents)) {
        trace->fraction = 1.0;
        return;
    }

    // might intersect, so do an exact clip
    clipHandle = SV_ClipHandleForEntity(touch);

    origin = touch->r.currentOrigin;
    angles = touch->r.currentAngles;

    if (!touch->r.bmodel) {
        angles = vec3_origin; // boxes don't rotate
    }

    CM_TransformedBoxTrace(trace, (float *) start, (float *) end,
            (float *) mins, (float *) maxs, clipHandle, contentmask,
            origin, angles, capsule);

    if (trace->fraction < 1) {
        trace->entityNum = touch->s.number;
    }
}

/*
====================
SV_ClipMoveToEntities

====================
 */
static void SV_ClipMoveToEntities(moveclip_t *clip) {
    int i, num;
    int touchlist[MAX_GENTITIES];
    sharedEntity_t *touch;
    int passOwnerNum;
    trace_t trace;
    clipHandle_t clipHandle;
    float *origin, *angles;

    num = SV_AreaEntities(clip->boxmins, clip->boxmaxs, touchlist, MAX_GENTITIES);

    if (clip->passEntityNum != ENTITYNUM_NONE) {
        passOwnerNum = (SV_GentityNum(clip->passEntityNum))->r.ownerNum;
        if (passOwnerNum == ENTITYNUM_NONE) {
            passOwnerNum = -1;
        }
    } else {
        passOwnerNum = -1;
    }

    for (i = 0; i < num; i++) {
        if (clip->trace.allsolid) {
            return;
        }
        touch = SV_GentityNum(touchlist[i]);

        // see if we should ignore this entity
        if (clip->passEntityNum != ENTITYNUM_NONE) {
            if (touchlist[i] == clip->passEntityNum) {
                continue; // don't clip against the pass entity
            }
            if (touch->r.ownerNum == clip->passEntityNum) {
                continue; // don't clip against own missiles
            }
            if (touch->r.ownerNum == passOwnerNum) {
                continue; // don't clip against other missiles from our owner
            }
        }

        // if it doesn't have any brushes of a type we
        // are looking for, ignore it
        if (!(clip->contentmask & touch->r.contents)) {
            continue;
        }

        // might intersect, so do an exact clip
        clipHandle = SV_ClipHandleForEntity(touch);

        origin = touch->r.currentOrigin;
        angles = touch->r.currentAngles;


        if (!touch->r.bmodel) {
            angles = vec3_origin; // boxes don't rotate
        }

        CM_TransformedBoxTrace(&trace, (float *) clip->start, (float *) clip->end,
                (float *) clip->mins, (float *) clip->maxs, clipHandle, clip->contentmask,
                origin, angles, clip->capsule);

        if (trace.allsolid) {
            clip->trace.allsolid = qtrue;
            trace.entityNum = touch->s.number;
        } else if (trace.startsolid) {
            clip->trace.startsolid = qtrue;
            trace.entityNum = touch->s.number;
        }

        if (trace.fraction < clip->trace.fraction) {
            qboolean oldStart;

            // make sure we keep a startsolid from a previous trace
            oldStart = clip->trace.startsolid;

            trace.entityNum = touch->s.number;
            clip->trace = trace;
            clip->trace.startsolid |= oldStart;
        }
    }
}

/*
==================
SV_Trace

Moves the given mins/maxs volume through the world from start to end.
passEntityNum and entities owned by passEntityNum are explicitly not checked.
==================
 */
void SV_Trace(trace_t *results, const vec3_t start, vec3_t mins, vec3_t maxs, const vec3_t end, int passEntityNum, int contentmask, int capsule) {
    moveclip_t clip;
    int i;

    if (!mins) {
        mins = vec3_origin;
    }
    if (!maxs) {
        maxs = vec3_origin;
    }

    Com_Memset(&clip, 0, sizeof ( moveclip_t));

    // clip to world
    CM_BoxTrace(&clip.trace, start, end, mins, maxs, 0, contentmask, capsule);
    clip.trace.entityNum = clip.trace.fraction != 1.0 ? ENTITYNUM_WORLD : ENTITYNUM_NONE;
    if (clip.trace.fraction == 0) {
        *results = clip.trace;
        return; // blocked immediately by the world
    }

    clip.contentmask = contentmask;
    clip.start = start;
    //	VectorCopy( clip.trace.endpos, clip.end );
    VectorCopy(end, clip.end);
    clip.mins = mins;
    clip.maxs = maxs;
    clip.passEntityNum = passEntityNum;
    clip.capsule = capsule;

    // create the bounding box of the entire move
    // we can limit it to the part of the move not
    // already clipped off by the world, which can be
    // a significant savings for line of sight and shot traces
    for (i = 0; i < 3; i++) {
        if (end[i] > start[i]) {
            clip.boxmins[i] = clip.start[i] + clip.mins[i] - 1;
            clip.boxmaxs[i] = clip.end[i] + clip.maxs[i] + 1;
        } else {
            clip.boxmins[i] = clip.end[i] + clip.mins[i] - 1;
            clip.boxmaxs[i] = clip.start[i] + clip.maxs[i] + 1;
        }
    }

    // clip to other solid entities
    SV_ClipMoveToEntities(&clip);

    *results = clip.trace;
}

/*
=============
SV_PointContents
=============
 */
int SV_PointContents(const vec3_t p, int passEntityNum) {
    int touch[MAX_GENTITIES];
    sharedEntity_t *hit;
    int i, num;
    int contents, c2;
    clipHandle_t clipHandle;
    float *angles;

    // get base contents from world
    contents = CM_PointContents(p, 0);

    // or in contents from all the other entities
    num = SV_AreaEntities(p, p, touch, MAX_GENTITIES);

    for (i = 0; i < num; i++) {
        if (touch[i] == passEntityNum) {
            continue;
        }
        hit = SV_GentityNum(touch[i]);
        // might intersect, so do an exact clip
        clipHandle = SV_ClipHandleForEntity(hit);
        angles = hit->s.angles;
        if (!hit->r.bmodel) {
            angles = vec3_origin; // boxes don't rotate
        }

        c2 = CM_TransformedPointContents(p, clipHandle, hit->s.origin, hit->s.angles);

        contents |= c2;
    }

    return contents;
}


